How your smartphone could one day predict the weather

The article suggests that with humidity and barometric pressure measurements alone, it would be possible to predict the weather using a network of cell phones.  I guess this approach would have to filter out data from a cell phone, for example, in an air conditioned building where the air is essentially dehumidified in the cooling process, or a cell phone in in an oil heated building during the winter in the northern U.S., where the air becomes extremely dry.  Anyhow, the idea is  interesting and might be applicable for many other types of sensors that could estimate, for example, solar energy, air quality, human stress levels, traffic patterns, etc..